Kim Je-Ha (Ji Chang-Wook) is former solider for hire. He is also called K2. He is hired as a bodyguard by Choi Yoo-Jin (Song Yoon-A). Choi Yoo-Jin is the wife of a presidential candidate (Cho Seong-Ha) and the daughter from a chaebol family. Meanwhile, Ko An-Na (Yoona) is the secret daughter of the presidential hopeful. She is also a recluse.